The rapid increases in demands for higher unit area production and quality crops with less labor have opened worldwide demands for full integration and interfacing of new plant culturing practices and machine systems. Billions of plants/seedlings/plugs/cuttings are transplanted yearly in various sectors of agriculture and forestry with tremendous amount of human labor, causing a major bottleneck in the production systems. Mechanization and automation are as important for plant-growers/farmers as it is for any other field of agriculture. This is because there is a tremendous amount of labor involved in the operation of a nursery, and the growers/farmers have to contend with the problems of production efficiency, scarcity of labor and overall labor costs just as any other business.
In seedling culturing practices one particular labor-intensive area is that of transferring and transplanting relatively young and small plants from their initial rooting containers to larger plant containers or to the field for further growth and development. A great deal of nurseries and plant producing facilities generally perform this operation by hand. Consequently, plant transfer and transplanting are time consuming and very inefficient. As a practical matter, the use of manual labor to transplant such plants severely limits the capacity of a farm or nursery for handling such transfer or transplanting operations. Therefore, there is and continues to be, a need for a fully automatic plant transfer and transplanting system that will automatically transfer and transplant plants/seedlings/plugs from an initial growing tray/container to a transfer area or second container for further growth and development in order to produced a superior plant in a greenhouse or in the field. Labor cost and availability, high costs of automation, as well as the inherent difficulties of plant/seedling/plug/cutting handling with a mechanical gripper (the main cause of misses, damages and unreliability) are the key problems to be resolved.
The innovative plant root-air-pruning technologies invented by Dr. Barney K. Huang have demonstrated many advantages including: elimination of root-binding, promotion of properly oriented root-branching for increased root-mass and vigorous growth, increased yields and quality, increased utilization cycles of greenhouse facilities, and savings on growth media, energy and fertilizer. The root-air-pruning concept allows the development of unique trays that lends itself to a simple automated/robotic transplanting system such as that disclosed by Dr. Barney K. Huang in U.S. Pat. Nos. 5,179,800, 5,254,140, 5,298,041, 5,573,558 and 6,357,180. Air-pruning tray-cells/pots has open bottoms with detachable screens. The tray-cells/pots are larger at the bottom and smaller at the top to eliminate the inherent disadvantages of traditional tray-cells/pots that have smaller closed bottom with drain hole(s) and larger open top that makes the container-sidewall tapered outward toward the top resulting in improper sidewall angle to cause root binding (root spiraling and tangling), slow and non-uniform growth.
The air-pruning tray-cell/pot/container design also utilizes the plant shoot characteristic that allows the foliage to fold together to go through the cell opening as the plant is pulled from the bottom or pushed from the top. This plant characteristic lends itself to an easy dislodging of the plant from the open cell/pot bottom and to the fully automated transplanting without using any types of grippers. Practical large scale field applications indicated that air-pruned cuttings and seedlings are significantly superior in growth performance both in the trays/containers and after transplanting and that effective fully automatic transplanting can be performed with the air-pruned plants/seedlings/plugs for various crops. However, many growers/farmers currently own transplanting machines and equipment, which were designed for transitional trays/flats/pots, yet, they want to use air-pruning trays/flats/pots which provide them with increased plant production, quality and yields. Therefore, there has been and continues to be a need for air-pruning trays/flats/pots that effectuate air-pruning but will allow the plugs/seedlings/plants to be removed from the top of air-pruning trays/flats/pots.